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Vasoactive drugs produce selective changes in flow to experimental brain tumors
Author(s) -
Panther Lori A.,
Baumbach Gary L.,
Bigner Darell D.,
Piegors Donald,
Groothuis Dennis R.,
Heistad Donald D.
Publication year - 1985
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410180614
Subject(s) - blood flow , cerebral blood flow , vasoactive , medicine , vasodilation , hypercapnia , brain tumor , norepinephrine , blood–brain barrier , cerebrum , endocrinology , pathology , central nervous system , dopamine , respiratory system
Abstract Most vasoactive drugs do not readily penetrate the blood‐brain barrier and do not affect cerebral blood flow. We tested the hypothesis that vasoactive drugs may alter blood flow to brain tumors in which the blood‐brain barrier is abnormal. Blood flow was measured with microspheres in dogs with brain tumors induced by avian sarcoma virus. Intravenously administered adenosine increased blood flow to tumor more than twofold but did not alter flow to normal brain. Intravenously administered norepinephrine decreased blood flow to tumor but not to normal brain. Thus, vasoactive drugs, which have little effect on blood flow to normal cerebrum, produce large changes in blood flow to brain tumors. We also examined responses to systemic hypercapnia. Hypercapnia increased blood flow to normal cerebrum more than twofold but failed to increase flow to tumors. Impaired vasodilator responses to hypercapnia in brain tumors, which cannot be explained primarily by an abnormality of the blood‐brain barrier, probably reflect another fundamental difference between vessels in normal brain and brain tumors. The finding that vasoactive drugs have selective effects on blood flow to brain tumors has important implications for delivery of lipid‐soluble chemotherapeutic drugs to the tumors.